Teaching the microscopic examination of urine sediment to second year medical students using the Urinalysis-Tutor computer program

Departments of
¹ Laboratory Medicine and
² Medical Education, University of Washington, Seattle, WA 98195.
³ Division of Nephrology and Transplantation, Virginia Mason Medical Center, Seattle, WA 98111.
^a Address correspondence to this author at: Department of Laboratory Medicine, Box 357110, University of Washington, Seattle, WA 98195-7110. Fax 206-548-6189; e-mail astion{at}mail.labmed.washington.edu.

	Abstract

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The microscopic examination of urine sediment is a common diagnostic tool taught to medical students, medical technologists, and others. The urine microscopic exam is difficult to teach because supervised instruction and textbook-based teaching suffer from numerous drawbacks. Here, we describe Urinalysis-Tutor, a computer program that uses digitized microscope images and computer-based teaching techniques to systematically teach the urine microscopic exam. In addition, we report the results of a 2-year study that evaluated the effectiveness of the program in 314 second year medical students who were required to use the program. The program contained two, 20-question exams. In the first year of the study (1996), one of the exams was chosen as the pretest and the other as the posttest; the pretest had to be completed before the students viewed the contents of the program, and the posttest was taken after finishing the tutorial. In 1997, the order of the two exams was reversed. In 1996, 159 students completed the study. The mean pretest score was 34% (SD, 14%), the mean posttest score was 71% (SD, 13%), and the improvement was significant (P <0.001, paired t-test). In 1997, 155 students participated. The mean pretest score was 41% (SD, 11%), the mean posttest score was 71% (SD, 13%), and the improvement was significant (P <0.001, paired t-test). The study shows that Urinalysis-Tutor helps medical students learn to interpret the microscopic appearance of urine sediment and that it is feasible to implement this tutorial in a medical school class.

	Introduction

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Routine analysis of urine is a part of the education of medical students, medical technologists, and other healthcare workers because the analysis of urine chemical constituents, coupled with a careful review of the microscopic elements in urine sediment, can provide physicians with valuable diagnostic information.

The most common approaches to teaching the examination of urine sediment are supervised instruction at a microscope and review of photomicrographs. These approaches have serious drawbacks. Supervised instruction suffers from variability in microscope quality and instructor experience. In addition, many medical schools, medical technology programs, and clinical laboratories do not have the time, the staffing, or the equipment to provide proper supervised instruction. Lastly, specimens that adequately demonstrate the most important urine elements may not be available, and even when available, the samples are often difficult to preserve for demonstration.

Although textbooks of photomicrographs (1)(2) can demonstrate rare specimens usually unavailable to instructors, the quality of photos is variable and often does not faithfully represent what the student views through the microscope. It is also difficult to use photographs to accurately demonstrate the various microscope techniques necessary to characterize specimens. These techniques include polarization, phase contrast, adjusting the plane of focus, simple manipulation of the light, and cell enumeration.

Over the last several years, faculty and staff in the University of Washington Department of Laboratory Medicine have been developing computer programs to teach image-based laboratory tests (for review, see (3)). The goal has been to use computer technology to overcome some of the drawbacks of traditional instruction. Our previous work includes PeripheralBlood-Tutor (4)(5) (Lippincott-Raven Publishers), which teaches the interpretation of peripheral blood smears; GramStain-Tutor (6)(7)(8) (Lippincott-Raven), which teaches the interpretation of direct Gram stains of body fluids; Electrophoresis-Tutor (9) (Beckman Instruments), which teaches the interpretation of protein electrophoresis of serum, urine, and cerebrospinal fluid; Parasite-Tutor (10) (Lippincott-Raven), which teaches the microscopic identification of clinically important parasites; and ANA-Tutor (11) (Sanofi Diagnostics Pasteur), which teaches the interpretation of the immunofluorescence assay for anti-nuclear antibodies, and others (12–14).

The focus of this article is Urinalysis-Tutor^TM (15) (published and distributed by Lippincott-Raven Publishers and also distributed by Bayer Diagnostics), a computer program that uses digital images, text, and microscope simulations to teach the microscopic examination of urine sediment to medical students, medical doctors, medical technologists, and other healthcare workers. We discuss the contents of Urinalysis-Tutor, concentrating on useful features of computer-based teaching, and we detail the results of a 2-year study of >300 second year medical students who were required to use the program in their course on the urinary system. The study suggests that Urinalysis-Tutor is feasible to implement in the medical school curriculum and that it helps teach the interpretation of the microscopic appearance of urine sediment.

	Materials and Methods

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program development
Urinalysis-Tutor was written in Microsoft Visual Basic for Windows (Microsoft Corp.). The program runs under Windows on a computer with the following minimal hardware configuration: 80486 computer running at 33 megahertz and equipped with 40 megabytes of hard disk storage or a CD-ROM drive. The minimal display resolution is 640 x 480, 256 colors.

The program was developed by a team of physicians, medical technologists, computer programmers, and artists. An early version of the program was tested by medical technologists from the University of Washington Medical Center (Seattle, WA) and the Harborview Medical Center (Seattle, WA). The feedback from this beta testing was used to prepare the final version of the program.

The program is based on images collected from fresh urine sediments that were prepared in the clinical laboratories at the University of Washington Medical Center and the Harborview Medical Center. The images were collected using a digital video microscope system, which has been described previously (5). Briefly, the hardware components of the system were as follows: a color CCD camera (Javelin Chromachip II model JE3462RGB, Javelin Electronics) mounted on a light microscope (Olympus model BH2, Olympus Inc.), an 80486 computer (Gateway 2000 Inc.) containing a video imaging board (MVP-AT, Matrox Electronic Systems Ltd), and a 13-inch closed circuit television monitor (Sony) for image display. The imaging board converted the analog camera signal into a digital image, which could then be saved and edited. The imaging system was operated using Optimas image analysis software (Optimas Corp.). Adobe Photoshop (Adobe Systems Inc.) was used to edit some of the digital images. Image enhancement could include color correction, noise reduction, and contrast and brightness adjustment; the goal of image enhancement was to make the images appear nearly identical to images seen using a high-quality microscope.

medical student evaluation
The subjects in the study were medical students at the University of Washington, who were required to use Urinalysis-Tutor in the second year, 34-h course on the urinary system (Human Biology 562). Directions for use of the program were given at the beginning of the 8-week course. The students could use the program any time during the course by logging onto any of 15 networked computers located in the University of Washington Health Sciences Library.

The first class to use the program was 159 students who entered medical school in August 1994 and who used the program in March and April of 1996. The second class was 155 students who entered in August 1995 and used the program in March and April of 1997.

The version of the program used for the study had two distinct 20-question exams. In the first year of the study (1996), one of the exams was chosen as the pretest and the other as the posttest. The program required the students to take the pretest immediately after logging into the program and before they could view the contents of the program. The posttest was taken after completing Urinalysis-Tutor. In year 2 of the study (1997), the exam order was reversed to assess the equivalency of the pre- and posttests. Thus, the 1996 pretest was used as the 1997 posttest, and the 1996 posttest became the 1997 pretest. Except for the reversal of the tests, the program used in 1996 was the same as that used in 1997.

Student identification numbers and test scores were recorded over the network in a Microsoft Access^® database (Microsoft Corp.). SPSS for Windows, Ver. 7.0 (SPSS Inc.) was used for statistical analysis. Student pretest and posttest data were compared with paired t-tests and analysis of covariance (ANCOVA).

program description
Urinalysis-Tutor requires little or no experience with computers. It is driven completely by pointing with the mouse and clicking the left mouse button. No supplementary reading materials are necessary to use or to understand the contents of the program, and it takes 90–120 min to complete the program.

A schematic of the contents of Urinalysis Tutor is shown in Fig. 1 . The program is divided into the following sections: Introduction, Urine Sediment Structures, Disease Associations, Image Atlas, and Final Exam.

View larger version (38K): [in this window] [in a new window]   Figure 1. Schematic of the Urinalysis-Tutor computer program. See Materials and Methods for details.

The introduction uses two-dimensional illustrations, three-dimensional illustrations, photographs, and microscope images to teach renal anatomy, the formation of urine, the basic steps in the laboratory examination of urine, and an introduction to phase contrast microscopy, polarizing microscopy, and the use of stains. Details of urine chemistry are not covered in Urinalysis-Tutor.

The section on urine sediment structures is the largest and most important part of the program. This section is divided into subsections on cells, casts, crystals, and organisms/artifacts. The cells that are detailed are white blood cells, red blood cells, epithelial cells, and oval fat bodies. A number of computer techniques help the student learn to identify and enumerate cells. For example, to learn the enumeration of red and white cells, the student simulates moving the stage of the microscope to look at multiple fields, and the program provides immediate feedback regarding whether the student has correctly identified each cell in an image. Furthermore, in the discussion of oval fat bodies, the student can change the microscope from a bright field to a polarizing configuration to reveal the "Maltese cross" forms that identify cholesterol-containing oval fat bodies.

The tutorial covers the following casts: hyaline, granular, waxy, fatty, renal cell, red cell, and white cell. Two- and three-dimensional illustrations as well as an animation are used to illustrate how casts are formed, and three to four images of each type of cast are shown with descriptive text overlays. A variety of teaching techniques enhance the discussion of casts. For example, the user can change the plane of focus to help identify a hyaline cast. In addition, by pressing a highlight button, some casts that can be difficult to find, e.g., hyaline, granular, waxy, fatty, or renal casts, will be delimited by a red border (Fig. 2 ). The highlighting feature is also used to point out the location of some of the visible red cells in a red cell cast and some of the white cells in a white cell cast. Another computer technique used to teach the identification of casts is the ability to change from bright field microscopy to either polarization or phase contrast microscopy. This mimics the way a practicing medical technologist might change microscope configuration to help identify a cast. A change in microscope configuration is available several times, including identifying a fatty cast, using polarization microscopy, and identifying a hyaline cast, using phase contrast.

View larger version (99K): [in this window] [in a new window]   Figure 2. Examples from the casts section of Urinalysis-Tutor. (A) A typical screen from the casts section of Urinalysis-Tutor showing an image of a waxy cast. Other images of casts (e.g., hyaline, granular, fatty, and others) can be viewed by selecting the buttons on the top of the screen. More examples of waxy casts can be displayed by selecting the "Examples" button located at the lower left of the screen. (B) The image after the user selected the "Highlight" button located directly below the image. This button allows the user to outline the waxy cast with a red border.

The section on crystals presents images of both normal and abnormal crystals. The normal crystals that are covered are uric acid, hippuric acid, calcium oxalate, triple phosphate, calcium carbonate, calcium phosphate, and ammonium biurate. The abnormal crystals are leucine, tyrosine (Fig. 3 ), cystine, bilirubin, cholesterol, sulfonamide, and radiopaque dye. For each crystal, there are two to four distinct images with optional descriptive text overlays and additional bulleted text describing pH and solubility characteristics of the crystals and the disease states associated with each abnormal crystal. The crystals section incorporates computer techniques such as the ability to simulate polarization microscopy to distinguish uric acid crystals from cystine crystals and the ability to completely delimit the irregular shape of an ammonium biurate crystal.

View larger version (101K): [in this window] [in a new window]   Figure 3. Examples from the abnormal crystals section of Urinalysis-Tutor. (A) A typical screen from the abnormal crystals section of Urinalysis-Tutor showing an image of tyrosine crystals. Other images of abnormal crystals are viewed by selecting the buttons on the top of the screen. Two more examples of tyrosine crystals, including the one shown in (B), can be accessed by selecting the "Examples" button located at the lower left of the screen. These examples demonstrate variation in the appearance of the crystals.

The section on organisms and artifacts covers yeasts, a parasite (Trichomonas vaginalis), bacteria, sperm, fibers, and starch. An example of each is presented. A number of computer teaching techniques are featured, including the ability to completely highlight all organisms and the ability to invoke polarization microscopy to identify fibers.

The Disease Associations section defines glomerulonephritis, nephrotic syndrome, pyelonephritis, and lower urinary tract infections, and then allows the user to review the characteristic microscopic findings associated with each condition. The image index is a reference tool that allows access to 91 microscope images in the program. The images are listed under the following categories: cells (15 images), casts (23 images), normal crystals (21 images), abnormal crystals (21 images), and organisms/artifacts (11 images). The images can be viewed one or two at a time, and the text overlays can be added or removed by clicking a button. The ability to directly compare any two images in the index is a major advantage of the computer program over a textbook. This is illustrated in Fig. 4 , which shows how a split screen can be used to help the student to differentiate uric acid crystals from cystine crystals.

View larger version (132K): [in this window] [in a new window]   Figure 4. The split-screen feature of the image index. The upper panel in the screen shows cystine crystals and uric acid crystals without polarization; the lower panel shows the same crystals under polarizing conditions. Only the uric acid crystals are birefringent.

The two final exams each have 20 image-based questions. The questions are in a variety of formats ranging from straightforward identification of urine sediment structures in a single image (Fig. 5 ) to the identification of multiple structures, using a microscope simulation to change microscope configurations (e.g., phase contrast or polarization microscopy), or to search the multiple fields in a slide for the structures. For each question, a detailed answer is provided. Users are given their scores at the end of the exam.

View larger version (120K): [in this window] [in a new window]   Figure 5. An exam question from Urinalysis-Tutor, which tests the ability to recognize white blood cells, transitional epithelial cells, and squamous epithelial cells. The question is presented in (A) and the answer in (B). The user chose the answers correctly.

	Results

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The results for the two medical student classes who used Urinalysis-Tutor are shown in Table 1 .

In 1996, 159 students completed the tutorial; in 1997, 155 students completed the tutorial. In both years of the study, the improvement from pretest to posttest was significant (P <0.001, paired t-test). Although the average score on the pretest in 1997 (41%; SD, 11%) was greater than the average score on the 1996 pretest (34%; SD, 14%) this difference was not significant.

The purpose of reversing the exams between 1996 and 1997 was to control for the difficulty of the two exams. Ideally, the exams would be of equivalent difficulty, so that a pre- to posttest improvement could not be solely because of a less difficult posttest. Because 1996 and 1997 class performances were similar despite reversal of the tests, the pretest and posttest are approximately equivalent, and the improvement in test scores between pretest and posttest was because of learning the material and not because of a less difficult posttest.

	Discussion

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The examination of urine sediment is one of many clinical laboratory procedures that require the proper interpretation of microscope images. Other common microscope-based diagnostic tests include peripheral blood smears, direct Gram stains, wet mounts of vaginal discharge, the direct detection of parasites, the direct detection of fungi, and the anti-nuclear antibody test and related immunofluorescence assays for autoantibodies.

Physicians, such as family practitioners and general internists, commonly perform a subset of the microscope-based tests, most notably urine dipstick and microscopic examination, the direct Gram stain, peripheral blood smears, and wet mounts (16). Therefore, it is not surprising that directors of internal medicine residencies, physicians who teach internal medicine to medical students, and residents in training agree that it is important to master these laboratory procedures (17–19). Despite the perceived importance of this training, training of residents and students is inadequate, as measured by surveys as well as by testing of physicians (17, 19). For example, Hilborne et al. (19) reported the poor performance of residents in performing urine microscopic exams and other image-based laboratory procedures. This has led many to conclude that more formal training is necessary in medical school, in residencies, and as part of continuing medical education for practicing physicians (17)(18)(19).

The most important reason that microscope-based laboratory tests are not adequately taught to medical doctors is that the two most common teaching approaches, supervised instruction at a microscope and textbook-based teaching, have serious disadvantages. Supervised instruction requires a great deal of resources, including specimens, microscopes, and an instructor's time. Textbooks have variable image quality and cannot simulate the manipulation of the microscope. The difficulty of teaching microscope-based laboratory procedures in the medical curriculum has caused many medical schools to reduce the teaching of these tests.

To overcome the problems associated with teaching microscope-based laboratory tests, our faculty in the Department of Laboratory Medicine has developed Urinalysis-Tutor and related computer programs, including GramStain-Tutor (6)(7)(8), PeripheralBlood-Tutor (4)(5), Parasite-Tutor (10), and ANA-Tutor (11). In addition, we have developed Microscopy-Tutor (20) (Lippincott-Raven), a program that complements the above programs by teaching the principles and practice of light microscopy. Our educational software is currently in wide use at the University of Washington in the medical school curriculum, the medical technology program, the pathology and other residency programs, the nurse practitioner curriculum, and other undergraduate and graduate programs. It is also in use in >3000 sites worldwide.

In this work, we studied the required use of the Urinalysis-Tutor in two consecutive classes (n = 159 and n = 155) of second year medical students. The improvement in scores between the exam taken before the tutorial and the exam taken after the tutorial shows that Urinalysis-Tutor helped students interpret the microscopic examination of urine sediment. This result is similar to results obtained in our previous studies of two of our other programs, GramStain-Tutor, which was studied in >140 first year medical students over 2 years(8); and PeripheralBlood-Tutor, which was studied in >250 second year medical students over 2 years (5). All three studies show that it is relatively easy to implement the tutorials in a medical school class using a library-based computer network. All three of the programs continue to be required in the preclinical medical school curriculum, and they are also being used optionally in the third year clerkship in internal medicine.

Urinalysis-Tutor is used frequently in our clinical laboratory for training, continuing education, and as a reference. Our laboratory also uses a related program that we developed, Urinalysis-Review (21) (Lippincott-Raven), which provides additional exam questions. Currently, Urinalysis-Review is being distributed four times per year to participating laboratories and schools, the goal being to allow supervisors and teachers to periodically monitor individual and group performance regarding the ability to interpret a urine microscopic exam. Urinalysis-Review can be a stand-alone program, or it can integrate with Urinalysis-Tutor because the images from Urinalysis-Review are accessible from the Urinalysis-Tutor image index if the tutorial is run on the same computer.

Our future work will include a more detailed analysis of the Urinalysis-Tutor exam data (22). This study is determining the urine sediment structures that are most difficult for medical students to learn. The results will be used to modify Urinalysis-Tutor, and then the effectiveness of the revised tutorial will be studied in the next two classes of second year medical students. Thus, our current software development model, as illustrated by our work with Urinalysis-Tutor, is to create a computer tutorial, to study its effectiveness, to establish that it is feasible to use in a large class, and then to use the results of the study as the basis for improvements in the next version of the software. We hope to apply this model to many of our tutorials.

	Acknowledgments

 
We thank the staffs of the clinical chemistry laboratories at the University of Washington Medical Center and Harborview Medical Center for participating in the evaluation of Urinalysis Tutor and providing quality specimens. In addition, we thank Chuck Rohrer for help with content of the tutorial, Jennifer Lee and Nathan Kalat for programing, Len Pagliaro for help with our digital video microscope, and Cathy Griffin for help regarding general computing issues. Additional information about educational software from the University of Washington Department of Laboratory Medicine can be found on the department's world wide web site at: http://www.labmed.washington.edu/Tutors/Tutor.Home.html, or at the web site for Lippincott-Raven Publishers: http://www.lrpub.com/.

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